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ASTM A217 WC11 (1¼Cr-½Mo) Valve

WC11 Chrome-Moly Alloy Steel

ASTM A217 WC11 is a 1.

Form

Cast

Max Temp

+538°C (+1000°F)

Min Temp

−29°C (−20°F)

Category

Alloy Steel

What is ASTM A217 WC11 (1¼Cr-½Mo)?

ASTM A217 WC11 (1¼Cr-½Mo) (WC11 Chrome-Moly Alloy Steel) is a alloy steel valve material. ASTM A217 WC11 is a 1.25% chromium, 0.50% molybdenum alloy steel casting grade, representing an intermediate step between the carbon steel WCB/WCC grades and the higher-alloy WC6 (2¼Cr-½Mo) and WC9 (2¼Cr-1Mo) grades. Temperature range: −29°C to +538°C (−20°F to +1000°F) - ASME B16.34 pressure-temperature ratings apply.

Form:
cast
Max Temp:
+538°C (+1000°F)
Min Temp:
−29°C (−20°F)

Chemical Composition - ASTM A217 WC11 (1¼Cr-½Mo)

C ≤ 0.15–0.21%, Mn 0.50–0.80%, Si ≤ 0.60%, Cr 1.00–1.50%, Mo 0.45–0.65%, P ≤ 0.020%, S ≤ 0.020%. Min yield 275 MPa (40 ksi). UNS J11872.

Temperature Range

−29°C to +538°C (−20°F to +1000°F) - ASME B16.34 pressure-temperature ratings apply

Maximum Temperature

+538°C (+1000°F)

Minimum Temperature

−29°C (−20°F)

Vajra Industrial Solutions manufactures and supplies valves in ASTM A217 WC11 (1¼Cr-½Mo) (WC11 Chrome-Moly Alloy Steel) for fossil fuel power plant main steam service, 371°c–510°c at class 300–600, with EN 10204 3.1 material traceability on every order.

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Equivalent Grades - ASTM A217 WC11 (1¼Cr-½Mo)

StandardEquivalent Grade
EN / DIN1.7706 - GX15CrMo1 (approximate)
ASME B16.34Group 1.9
BSGrade B2 (approximate)
JISSCPH 32 (approximate)

Suitable Services

Fossil fuel power plant main steam service, 371°C–510°C at Class 300–600

Refinery vacuum and atmospheric distillation - hot oil lines, 400–500°C

Industrial steam boiler headers and main steam isolation valves

Feedwater heater and de-aerator valves in large thermal power stations

Petrochemical service in moderate-temperature, moderate-pressure hydrocarbon streams

Not Suitable For

Sour (H₂S) service without stringent PWHT and hardness control per NACE MR0175

High-temperature hydrogen (above 300°C) - WC11 is not listed in API 941 Nelson curves for H₂; use F22 or F91

Cryogenic or low-temperature service below −29°C - use A352 LC grades

Valve Body Applications

Main steam and reheat steam valve bodies in fossil-fuel power plants, Class 300–600

Hot oil and vacuum distillate valve bodies in refinery units, 371–510°C

High-temperature boiler feed water pump suction and discharge valves

Intermediate-temperature gate and globe valve bodies where WCB is inadequate

Trim Applications

Stems and bonnets in alloy steel gate and globe valves

Bonnet bolting and packing followers in high-temperature service

Typical Valve Types in ASTM A217 WC11 (1¼Cr-½Mo)

Gate valves: Class 300–600, alloy steel, power plant main steam

Globe valves: Class 600–900 throttling valves in hot oil service

Check valves: swing check, Class 300–600, steam and hot hydrocarbon

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Reviewed by Materials Engineering, Vajra Industrial SolutionsDiscipline: Valve Metallurgy & Materials SelectionLast reviewed: 20 June 2026

Connected Engineering

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We supply ASTM A217 WC11 (1¼Cr-½Mo) (WC11 Chrome-Moly Alloy Steel) valves with full certification documentation — EN 10204 3.1/3.2 MTCs and hydrotest certs as standard.